The use of wireless or telecommunication devices such as a cellular phone has greatly increased through the years. As a result, these telecommunication devices are being used in a large variety of environments ranging from inside moving vehicles, to crowded cafes, to windy beaches. Many of these environments are noisy environments which pose special problems for service providers to provide acceptable signal quality to their users.
For many conventional telecommunication devices, a microphone is placed near a speaking user's mouth and will pick up speech signals. Unfortunately, the microphone will also pick up background noise, which can greatly degrade the quality of the speech signal transmitted to all of the parties involved in the call. Many noise cancellation methods have been developed for single microphone systems, but they tend to still result in substandard quality when used in noisy conditions.
Better noise cancellation can be achieved using multiple microphones located on the telecommunication device. The multiple microphone techniques exploit spatial selectivity and can suppress non-stationary noises such as babbling noise produced by people talking in the background. However, many of these systems still assume a standard location of the microphones in relation to the speaker's mouth. A problem occurs when the speaker does not hold the communication device in the standard configuration.
One system designed to overcome such problems is disclosed in U.S. patent application No. 2007/0230712. In this system, two microphones are used to capture an acoustic signal including the desired voice signal and an unwanted noise signal. The telecommunication device includes an orientation sensor for measuring a one dimensional orientation of the communication device, i.e., how the telecommunication device is being held along the user's cheek, while the acoustic signal is being captured. An audio processing unit then processes the acoustic signal to remove some of the noise based on the measured orientation of the telecommunication device.
One problem with the disclosed multiple microphone technique is that the noise cancellation system relies only on the one dimensional orientation measurement along the cheek of the user. Unfortunately, different users hold their telecommunication devices in a variety of ways, which results on various distances between the user's mouth and the telecommunication device and distances between the user's ear and the telecommunication device. Thus, there is a need for a method and apparatus for providing noise cancellation in a received acoustic signal based on a three dimensional orientation measurement of the telecommunication device.